I have basically zero nostalgia for the Dreamcast, but those devices that replace disc drives with flash memory are amazing. Nice work!
The great thing about emulation is the ability to mess around with games on relatively unpopular systems like the Dreamcast, TG16, and of course Sega CD, just to remind myself that I shouldn't spend hundreds of dollars to buy stuff that I would rarely play. Yeah, I fired up about half a dozen Sega CD games (and browsed my curated list) and decided against the MegaSD, at least for now. I will most likely play through Snatcher or Keio Flying Squadron or maybe even Popful Mail eventually, but I've got Sonic Mania and the Steam version of Sonic CD for some reason, though I'm not a huge fan. Otherwise, there just aren't enough great games on the Sega CD to warrant the investment at the moment.
Regarding the TG16/PC Engine, there are a ton of great games, but I like buying locally, so the cost is still prohibitive, due to low availability. I do appreciate the advice and links. It's interesting to see what's out there. So, thanks, Locke141!
I've also been avoiding classic consoles, even at deep discounts, because I know that I would be tempted to invest a decent amount of time modding them. I would have bought the SNES classic, as it was almost perfect out of the box, but the whole scalper thing just killed it for me. I've seen it discounted lately, usually without the packaging, but still not low enough to bite.